1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method thereof.
2. Related Art
Conventional semiconductor devices includes, for example, semiconductor devices described in Japanese Patent Laid-Open No. 2001-102,449. Cross-sectional views of the semiconductor devices described in Japanese Patent Laid-Open No. 2001-102,449 are shown in FIGS. 12A and 12B. As show in FIG. 12A, concerning a base layer 201 employed for manufacturing such semiconductor device, an electrode 400 is formed on the surface of the base layer 201, and a periphery of the electrode 400 is covered with an insulating layer 401, and is planarized.
Then, as shown in FIG. 12B, an Si3N4 layer 202, an organic spin-on-glass (SOG) film 203, an Si3N4 layer 204, an organic SOG film 207 and an Si3N4 layer 208 are sequentially deposited on the base layer 201, and trenches and holes are integrally formed via a dual damascene etch process. Then, Cu is embedded within these trenches and holes as an electric conductor layer 402 to form an interconnect circuit, thereby presenting the semiconductor device.
However, there are interfaces between the organic SOG film 203 and 207 that are low dielectric constant insulating films and the etch stop film that is an underlying layer film or Si3N4 layers 202, 204 and 208 that function as hard mask films of the upper layer films in the conventional technology described in Japanese Patent Laid-Open No. 2001-102,449, and the interfaces contact with the electric conductor layer 402.
In this structure, when time dependence dielectric breakdown (TDDB) is conducted between interconnects in the case that the interval between interconnects that are composed of portions of the electric conductor layer 402 (i.e., interval between the electric conductor layers 402) is narrow, a dielectric breakdown is occurred through these interfaces, so that a short-circuit between the interconnects composed of portions of the electric conductor layer 402 is occurred. This phenomenon becomes to be noticeable, as the dielectric constants of the organic SOG films 203 and 207, which are low dielectric constant insulating films, are reduced.